Video cameras capturing motion video imagery are commonly used in monitoring and/or surveillance. Typically, a network of cameras are arranged in order to cover a predetermined area. The video data captured may be recorded, viewed in real time, automatically analysed etc.
Mapping surveillance cameras and/or monitoring cameras onto a map showing a surveyed/monitored area is very useful for many applications. For example the map may be used to locate specific cameras for repair or simply to locate where a particular incident being captured on video really occurred. Moreover, the camera on the map may be paired with video streams originating from the specific camera in order to facilitate selection of a video stream related to the area in the map. The position data of the camera may also be recorded in the video in order to enable identification of where the video was captured.
This type of mapping may of course be performed manually by having a person checking where all the cameras are positioned and enter them onto a paper map or a digital map. The geographic positioning within the digital map may be performed by simply selecting a position in a map showed on a display or by entering coordinates representing the position of the camera. These coordinates may be given in any geographic coordinate system as long as the position is uniquely identified.
Manually identifying the positions of cameras may be laborious, tedious, and prone to errors. This is particularly true in large surveillance and/or monitoring systems including many cameras. However, methods for identifying the position of cameras in such systems have been developed in order to overcome these concerns. For example there are implementations in which each camera is provided with satellite navigation circuitry, e.g., GPS, GLONASS, Galileo, etc., and transmits its coordinates to a central server where the position is registered and indicated on a map. The geographic position may also or alternatively be inserted into the video stream, sometimes referred to as geo-tagging.
Another method for facilitating the collecting of the geographic position of the cameras in a camera network is described in the international patent application WO 2014/013015. The patent application describes a vehicle equipped with navigation equipment enabled to determine the geographic position of the vehicle. Further, the vehicle carries an optically recognizable structure, e.g., a checkerboard, light emitting equipment, texture with differentiable colour segments, and an optical transmitter arranged to transmit a unique identifier that is changing over time. Then, the vehicle is driven on streets within a surveyed area and continuously registering the position of the vehicle. The registered position is associated with the continuously changing identifier sent via the optical transmitter and both are sent to a computer system. Video cameras in the surveyed area are capturing images of the vehicle and send them to the computer system where the unique identifier is recognised in the images including the vehicle and each picture including the vehicle may be matched to a position registered by the navigation equipment in the vehicle. Then characteristics of a camera relating to position and direction may be calculated based on the position of the vehicle when the camera captured images of it and based on the location within the image for the vehicle.
This system facilitates the identification, collecting, and registration of geographical position of cameras in a surveillance and/or monitoring system. However, the system is still complex and requires a lot of fairly advanced hardware and post processing in order to yield adequate results.